Blue light compensation film and OLED display

ABSTRACT

The present invention provides a blue light compensation film and an OLED display. The blue light compensation film of the present invention effectively absorbs blue light with wavelength longer than blue wavelength and excite blue light by using a blue light upconversion luminescent material, and effectively improves color shift white OLED device caused by short lifespan of blue electroluminescent material to achieve blue light compensation of the white OLED device and solve the of yellowing in traditional OLED display with age. The OLED display of the present invention comprises the blue light compensation film to avoid color shift problem and provides good display quality.

CROSS REFERENCE TO RELATED APPLICATION

This is a divisional application of co-pending U.S. patent applicationSer. No. 15/329,239, filed on Jan. 25, 2017, which is a national stageof PCT Application No. PCT/CN2016/110905, filed on Dec. 20, 2016,claiming foreign priority of Chinese Patent Application No.201610890915.3, filed on Oct. 12, 2016.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to the field of display techniques, and inparticular to a blue light compensation film and OLED display.

2. The Related Arts

Since the Kodak developed the thin film organic light emitting diode(OLED) device in 1987, the development of the OLED device has been thecenter of attention in industry. After 30 years of development, the OLEDtechnology is widely applied in the field of lighting and display. TheOLED display is a flat panel display device and provides the advantagesof active light-emitting, low driving voltage, high emission efficiency,quick response time, high resolution and contrast, near 180° viewingangle, wide operation temperature range, and capability to realizeflexible display and large-area full-color display, and is regarded asthe most promising display technology.

The driving types of OLED can be divided, according to the drivingmethod, into the passive matrix OLED (PMOLED) and active matrix OLED(AMOLED), i.e., the direct addressable type and thin film transistor(TFT) addressable type, wherein the AMOLED provides the advantages ofpixels arranged in an array, self-luminous, and high luminous efficiencyand is commonly used for high definition large-size display.

An OLED typically comprises a substrate, an anode provided on thesubstrate, a hole injection layer (HIL) provided on the anode, a holetransport layer (HTL) provided on the hole injection layer, alight-emitting layer (EML) provided on the hole transport layer, anelectron transport layer (ETL) provided on the light-emitting layer, anelectron injection layer (EIL) provided on the electron transport layer,and a cathode provided on the electron transport layer. The theory oflight-emission of OLED display the carrier injection and recombinationfor the semiconductor materials and organic light-emitting materialsunder the driving of the electric field. Specifically, the OLED displayusually adopts the ITO pixel electrode and the metal electrode as theanode and the cathode. Under the driving of a certain voltage, theelectron and the hole are respectively injected from the cathode and theanode into the electron transport layer and the hole transport layerrespectively; and the electrons and the holes migrate through theelectron transport layer and the hole transport layer respectively tothe light-emitting layer to meet in the light emitting layer to formexcitons and to excite the light-emitting molecules, which in turn emitvisible light by radiation relaxation.

At present, in the field of display panel, the main application mode ofOLED is the whole surface evaporation with red (R), green (G) and blue(B) three-color electroluminescent materials, combined to form whiteOLED (WOLED) and in collaboration with color filter to achieve colordisplay. The above technology has been used by manufacturers to achievemass production.

The use of WOLED in collaboration with color filter to color display isstill basically based on OLED device, and the white light is achieved bymixing R, G, B electroluminescent materials. At present, the mainproblem encountered by the above technology is the lifespan of the blueelectroluminescent material, which leads to a yellowish tint in thecolor display after the display ages.

SUMMARY OF THE INVENTION

The object of the present invention is to provide a blue lightcompensation film, to effectively improve the color shift in white colorOLED device caused by the short lifespan of the blue electroluminescentmaterial, to solve the yellowing problem of traditional OLED display.

Another object of the present invention is to provide an OLED display,comprising the above blue light compensation film to avoid color shiftproblem and provide good display quality.

To achieve the above object, the present invention provides a blue lightcompensation film, which comprises, from the bottom up in a stack, anadhesive layer, a first transparent film, and a second transparent film;

the blue light compensation film satisfying at least one of the twofollowing conditions:

Condition 1: at least one of the adhesive layer, the first transparentfilm, and the second transparent film being doped with a blue lightupconversion luminescent material;

Condition 2: at least one of a first gap between the adhesive layer andthe first transparent film and a second gap between the firsttransparent film and the second transparent film being provided with ablue light upconversion luminescent material;

the blue light upconversion luminescent material comprising at least oneof an upconversion organic luminescent material based on atriplet-triplet annihilation and a host material doped with a rare earthion; the blue light upconversion luminescent material being capable ofabsorbing light with wavelength greater than the blue light wavelengthand converting to blue light.

According to a preferred embodiment of the present invention, the bluelight upconversion luminescent material absorbs light with wavelengthgreater than 630 nm and converts to blue light of wavelength 460 nm-490nm.

According to a preferred embodiment of the present invention, theupconversion organic luminescent material based on the triplet-tripletannihilation comprises at least one of a combination of bipyridineruthenium and 9,10-diphenylanthracene, and a combination oftetraphenylporphyrin platinum and perylen;

the bipyridine ruthenium has a structure of

the 9,10-diphenylanthracene has a structure of

the tetraphenylporphyrin platinum has a structure of

the perylen has a structure of

According to a preferred embodiment of the present invention, in thehost material doped with rare earth ion, the host material comprises atleast one of a halogen compound, an oxide, an oxyhalide, asulfur-containing compound, and a sulfur oxide; the rare earth ionscomprises at least one of Er³⁺, Tm³⁺, Dy³⁺, Tb³⁺, Ho³⁺, and Eu³⁺.

According to a preferred embodiment of the present invention, the firsttransparent film and the second transparent film respectively compriseone or more of a polyethylene terephthalate film, a polyimide film, acellulose triacetate film, and a cycloolefin polymer film; wherein thefirst transparent film and the second transparent film are a compositefilm of a single layer film or a multi-layer film, respectively.

According to a preferred embodiment of the present invention, thematerial for the adhesive layer comprises a pressure-sensitive adhesive.

According to a preferred embodiment of the present invention, inCondition 2, the blue light upconversion luminescent material is mixedwith a resin and cured on at least one of the first and second gaps toform a blue light upconversion luminescent material layer.

According to a preferred embodiment of the present invention, no bluetransparent luminescent material is provided between the firsttransparent film and the second transparent film, and the firsttransparent film and the second transparent film are a single unitarytransparent film.

Another embodiment of the present invention provides an OLED display,which comprises: an OLED device, and a blue light compensation filmprovided at the light-emitting side of the OLED device; the blue lightcompensation film is a blue light compensation film described above andthe blue light compensation film is attached to light-emitting side ofthe OLED device by the adhesive layer.

According to a preferred embodiment of the present invention, the lightemitted by the OLED device is white light, the luminescent material ofthe OLED device comprises a red electroluminescent material, a greenelectroluminescent material and a blue electroluminescent material; thewhite light emitted by the OLED device is formed by mixing the red lightemitted by the electroluminescent material, the green light emitted bythe green electroluminescent material, and the blue light emitted by theblue electroluminescent material.

Yet another embodiment of the present invention provides a blue lightcompensation film, which comprises, from the bottom up in a stack, anadhesive layer, a first transparent film, and a second transparent film;

the blue light compensation film satisfying at least one of the twofollowing conditions:

Condition 1: at least one of the adhesive layer, the first transparentfilm, and the second transparent film being doped with a blue lightupconversion luminescent material;

Condition 2: at least one of a first gap between the adhesive layer andthe first transparent film and a second gap between the firsttransparent film and the second transparent film being provided with ablue light upconversion luminescent material;

the blue light upconversion luminescent material comprising at least oneof an upconversion organic luminescent material based on atriplet-triplet annihilation and a host material doped with a rare earthion; the blue light upconversion luminescent material being capable ofabsorbing light with wavelength greater than the blue light wavelengthand converting to blue light;

wherein the blue light upconversion luminescent material absorbing lightwith wavelength greater than 630 nm and converting to blue light ofwavelength 460 nm-490 nm;

wherein the material for the adhesive layer comprising apressure-sensitive adhesive.

Compared to the known techniques, the present invention provides thefollowing advantages. The present invention provides a blue lightcompensation film which effectively absorbs blue light with wavelengthlonger than blue wavelength and excite blue light by blue lightupconversion luminescent material, and effectively improves color shiftwhite OLED device caused by short lifespan of blue electroluminescentmaterial to achieve blue light compensation of the white OLED device andsolve the of yellowing in traditional OLED display with age. The presentinvention also provides an OLED display comprising the aforementionedblue light compensating film to avoid color shift and provide gooddisplay quality.

BRIEF DESCRIPTION OF THE DRAWINGS

To make the technical solution of the embodiments according to thepresent invention, a brief description of the drawings that arenecessary for the illustration of the embodiments will be given asfollows. Apparently, the drawings described below show only exampleembodiments of the present invention and for those having ordinaryskills in the art, other drawings may be easily obtained from thesedrawings without paying any creative effort. In the drawings:

FIG. 1 is a schematic view showing a structure of the blue lightcompensation film provided by the first embodiment of the presentinvention;

FIG. 2 is a schematic view showing a structure of the blue lightcompensation film provided by the second embodiment of the presentinvention;

FIG. 3 is a schematic view showing a structure of the blue lightcompensation film provided by the third embodiment of the presentinvention;

FIG. 4 is a schematic view showing a structure of the blue lightcompensation film provided by the fourth embodiment of the presentinvention;

FIG. 5 is a schematic view showing a structure of the blue lightcompensation film provided by the fifth embodiment of the presentinvention;

FIG. 6 is a schematic view showing a structure of the OLED displayprovided by an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

To further explain the technique means and effect of the presentinvention, the following uses preferred embodiments and drawings fordetailed description.

The present invention achieves the blue light compensation effect of awhite OLED device by utilizing the property of an upconversionluminescent material, which is a material having an anti-Stokesluminescence property. The upconversion luminescent material is excitedby a low-energy light to emit high-energy light, which is opposite tothe Stokes luminescence mechanism. In other words, a low-frequency,short-wavelength light is absorbed to excite a high-frequency,long-wavelength light; for example, the absorption of infrared light toemit visible light, or absorb red light to emit the blue and greenlight. Unlike the typical luminescence process, which involving only onebase state and one excited state, the upconversion process requires manyintermediate states to accumulate the energy of the excitedlow-frequency photon.

Referring to FIGS. 1-5, the present invention provides a blue lightcompensation film 50, which comprises, from the bottom up in a stack, anadhesive layer 30, a first transparent film 10, and a second transparentfilm 20.

The blue light compensation film satisfies at least one of the twofollowing conditions:

Condition 1: at least one of the adhesive layer 30, the firsttransparent film 10, and the second transparent film 20 is doped with ablue light upconversion luminescent material.

Condition 2: at least one of a first gap between the adhesive layer 30and the first transparent film 10 and a second gap between the firsttransparent film 10 and the second transparent film 20 is provided witha blue light upconversion luminescent material.

The blue light upconversion luminescent material comprises at least oneof an upconversion organic luminescent material based on atriplet-triplet annihilation and a host material doped with a rare earthion; the blue light upconversion luminescent material is capable ofabsorbing light with wavelength greater than the blue light wavelengthand converting to blue light.

Specifically, the blue light upconversion luminescent material absorbslight with wavelength greater than 630 nm and converts to blue light ofwavelength 460 nm-490 nm.

Specifically, the blue light upconversion luminescent material isnano-scaled particles, having a particle diameter of 20-nm-100 nm.

Specifically, the upconversion organic luminescent material based ontriplet-triplet annihilation usually comprises a donor and a receptor, adonor electron transits to the receptor energy level, and two tripletsannihilate, a new energy level is generated to achieve a low energy intohigh-energy radiation.

Preferably, the upconversion organic luminescent material based on thetriplet-triplet annihilation comprises at least one of a combination ofbipyridine ruthenium and 9,10-diphenylanthracene (PDA), and acombination of tetraphenylporphyrin platinum and perylen.

The bipyridine ruthenium has a structure of

The 9,10-diphenylanthracene has a structure of

The tetraphenylporphyrin platinum has a structure of

The perylen has a structure of

Specifically, in the combination of the bipyridyl ruthenium and the9,10-diphenylanthracene, the bipyridyl ruthenium is a donor and the9,10-diphenylanthracene is a receptor.

Specifically, in the combination of the tetraphenylporphyrin platinumand perylene, the tetraphenylporphyrin platinum is a donor and theperylene is a receptor.

Specifically, in the host material doped with rare earth ion, the hostmaterial comprises at least one of a halogen compound, an oxide, anoxyhalide, a sulfur-containing compound, and a sulfur oxide; the rareearth ions comprises at least one of Er³⁺, Tm³⁺, Dy³⁺, Tb³⁺, Ho³⁺, andEu³⁺.

Specifically, the first transparent film 10 and the second transparentfilm 20 respectively comprise one or more of a polyethyleneterephthalate (PET) film, a polyimide (PI) film, a cellulose triacetate(TAC) film, and a cycloolefin polymer (COP) film; wherein the firsttransparent film 10 and the second transparent film 20 are a compositefilm of a single layer film or a multi-layer film, respectively.Specifically, the first transparent film 10 and the second transparentfilm 20 are formed by a hot press or a thermoplastic process.

Preferably, the material for the adhesive layer comprises apressure-sensitive adhesive (PSA).

Specifically, in Condition 2, the blue light upconversion luminescentmaterial is mixed with a resin and cured on at least one of the firstand second gaps to form a blue light upconversion luminescent materiallayer 40 (as shown in FIG. 4 and FIG. 5). Preferably, the resin is anepoxy resin.

As shown in FIG. 4, when the blue light upconversion luminescentmaterial layer 40 is disposed at the second gap between the firsttransparent film 10 and the second transparent film 20, the blue lightupconversion luminescent material layer 40 also serves to bond the firsttransparent film 10 and the second transparent film 20 due to theadhesive property of the resin.

Specifically, when no blue transparent luminescent material is providedbetween the first transparent film 10 and the second transparent film20, and the first transparent film 10 and the second transparent film 10are a single unitary transparent film.

Refer to FIG. 1, which is the first embodiment of the blue lightcompensation film 50 of the present invention. In the instantembodiment, the second transparent film 20 is doped with blue lightupconversion luminescent material.

Refer to FIG. 2, which is the second embodiment of the blue lightcompensation film 50 of the present invention. In the instantembodiment, the first transparent film 10 is doped with blue lightupconversion luminescent material.

Refer to FIG. 3, which is the third embodiment of the blue lightcompensation film 50 of the present invention. In the instantembodiment, the adhesive layer 30 is doped with blue light upconversionluminescent material.

Refer to FIG. 4, which is the fourth embodiment of the blue lightcompensation film 50 of the present invention. In the instantembodiment, the second gap between the first transparent film 10 and thesecond transparent film 20 is disposed with a blue light upconversionluminescent material layer 40.

Refer to FIG. 5, which is the fifth embodiment of the blue lightcompensation film 50 of the present invention. In the instantembodiment, the first gap between the adhesive layer 30 and the firsttransparent film 10 is disposed with a blue light upconversionluminescent material layer 40.

The blue light compensation film of the present invention effectivelyabsorbs blue light with wavelength longer than blue wavelength andexcite blue light by using a blue light upconversion luminescentmaterial, and effectively improves color shift white OLED device causedby short lifespan of blue electroluminescent material to achieve bluelight compensation of the white OLED device and solve the of yellowingin traditional OLED display with age.

Refer to FIG. 6, the present invention also provides an OLED display,which comprises: an OLED device 60, and a blue light compensation film50 provided at the light-emitting side of the OLED device 60. The bluelight compensation film is as described above and the blue lightcompensation film 50 is attached to light-emitting side of the OLEDdevice 60 by the adhesive layer 30.

Specifically, the light emitted by the OLED device 60 is white light,the luminescent material of the OLED device 60 comprises a redelectroluminescent material, a green electroluminescent material and ablue electroluminescent material; the white light emitted by the OLEDdevice is formed by mixing the red light emitted by theelectroluminescent material, the green light emitted by the greenelectroluminescent material, and the blue light emitted by the blueelectroluminescent material.

The above OLED display comprises a blue light compensation film, and isable to effectively improves color shift white OLED device caused byshort lifespan of blue electroluminescent material to achieve blue lightcompensation of the white OLED device and solve the of yellowing intraditional OLED display with age.

In summary, the present invention provides a blue light compensationfilm and an OLED display. The blue light compensation film of thepresent invention effectively absorbs blue light with wavelength longerthan blue wavelength and excite blue light by using a blue lightupconversion luminescent material, and effectively improves color shiftwhite OLED device caused by short lifespan of blue electroluminescentmaterial to achieve blue light compensation of the white OLED device andsolve the of yellowing in traditional OLED display with age. The OLEDdisplay of the present invention comprises the blue light compensationfilm to avoid color shift problem and provides good display quality.

It should be noted that in the present disclosure the terms, such as,first, second are only for distinguishing an entity or operation fromanother entity or operation, and does not imply any specific relation ororder between the entities or operations. Also, the terms “comprises”,“include”, and other similar variations, do not exclude the inclusion ofother non-listed elements. Without further restrictions, the expression“comprises a . . . ” does not exclude other identical elements frompresence besides the listed elements.

Embodiments of the present invention have been described, but notintending to impose any unduly constraint to the appended claims. Anymodification of equivalent structure or equivalent process madeaccording to the disclosure and drawings of the present invention, orany application thereof, directly or indirectly, to other related fieldsof technique, is considered encompassed in the scope of protectiondefined by the clams of the present invention.

What is claimed is:
 1. A blue light compensation film, which comprises,from a bottom up in a stack, an adhesive layer, a first transparentfilm, and a second transparent film; the blue light compensation filmsatisfying following condition: a gap between the adhesive layer and thefirst transparent film being provided with a blue light upconversionluminescent material; the blue light upconversion luminescent materialcomprising at least one of an upconversion organic luminescent materialbased on a triplet-triplet annihilation and a host material doped with arare earth ion; the blue light upconversion luminescent material beingcapable of absorbing light with wavelength greater than a blue lightwavelength and converting to blue light.
 2. The blue light compensationfilm as claimed in claim 1, wherein the blue light upconversionluminescent material absorbs light with wavelength greater than 630 nmand converts to a blue light of wavelength 460 nm-490 nm.
 3. The bluelight compensation film as claimed in claim 1, wherein the upconversionorganic luminescent material based on the triplet-triplet annihilationcomprises at least one of a combination of bipyridine ruthenium and9,10-diphenylanthracene, and a combination of tetraphenylporphyrinplatinum and perylen; the bipyridine ruthenium has a structure of

the 9,10-diphenylanthracene has a structure of

the tetraphenylporphyrin platinum has a structure of

the perylen has a structure of


4. The blue light compensation film as claimed in claim 1, wherein inthe host material doped with rare earth ion, the host material comprisesat least one of a halogen compound, an oxide, an oxyhalide, asulfur-containing compound, and a sulfur oxide; the rare earth ionscomprises at least one of Er3+, Tm3+, Dy3+, Tb3+, Ho3+, and Eu3+.
 5. Theblue light compensation film as claimed in claim 1, wherein the firsttransparent film and the second transparent film respectively compriseone or more of a polyethylene terephthalate film, a polyimide film, acellulose triacetate film, and a cycloolefin polymer film; wherein thefirst transparent film and the second transparent film are a compositefilm of a single layer film or a multi-layer film, respectively.
 6. Theblue light compensation film as claimed in claim 1, wherein a materialfor the adhesive layer comprises a pressure-sensitive adhesive.
 7. Anorganic light-emitting diode (OLED) display, which comprises: an OLEDdevice, and the blue light compensation film described in claim 1,wherein the blue light compensation film is attached to a light-emittingside of the OLED device by the adhesive layer.
 8. The OLED display asclaimed as in claim 7, wherein a light emitted by the OLED device iswhite light, a luminescent material of the OLED device comprises a redelectroluminescent material, a green electroluminescent material and ablue electroluminescent material; the white light emitted by the OLEDdevice is formed by mixing the red light emitted by theelectroluminescent material, the green light emitted by the greenelectroluminescent material, and the blue light emitted by the blueelectroluminescent material.